Service load bearing assembly for spreading out high induced stresses

ABSTRACT

Embodiments of the present invention provide a suspension assembly including a bolt made from a bolt material; a suspension component made from a suspension material, the suspension component having a suspension opening therethrough, the suspension opening having a geometry for insertion of at least a first portion of the bolt; and a bushing assembly including an elastomeric element and a bushing opening therethrough, the bushing opening having a geometry for insertion of at least a second portion of the bolt; wherein the suspension material has a yield strength that is substantially higher than a yield strength of the bolt material.

CROSS-REFERENCES TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.12/280,511, filed Aug. 22, 2008 now U.S. Pat. No. 7,914,021, which isthe National Stage of International Application No. PCT/US07/24212,filed Nov. 19, 2007, which claims the benefit of U.S. ProvisionalApplication No. 60/866,347, filed Nov. 17, 2006, each application ofwhich is hereby incorporated herein by reference in its entirety.

FIELD OF THE INVENTION

The embodiments disclosed herein relate generally to the field ofsuspension systems for vehicles, and more particularly to an offsetbushing mounting apparatus for use in the suspension systems ofvehicles.

BACKGROUND OF THE INVENTION

Suspension systems making use of elastomeric members or bushings betweena generally fixed portion of the frame of the vehicle and an end of ashock absorber, strut, or other type of cylinder or suspension memberare generally well known within the art.

Elastomeric bushings are generally used to reduce transmitted road noiseand suspension vibration, and are also generally flexible enough toallow for articulation or movement during suspension travel. Typically,a suspension arm includes at least one elastomeric bushing pivotablyattached to the vehicle frame.

In some car and light truck suspensions, tight clearances between thewheel or other components and suspension components require bushingsthat are offset or cantilevered from the suspension component.Typically, the geometric relationship of the cantilevered bushing to thesuspension component induces high bending moments on the interface ofthe bushing and the suspension component during vehicle service. Morespecifically, service loads induce high bending moments, andsubsequently high local stresses, in the portion of the suspensioncomponents connected to the bushing. Referring to FIG. 1, a force F of33.2 kN to an offset bushing, as typically experienced in automotive orlight truck applications, results in a stress of greater than 600 MPabeing induced to the suspension component 10 at the point ofconnectivity 100 to the offset bushing. These high local stressesrequire that the suspension component 10 be constructed from highstrength materials, i.e. forged steel, which precludes the use oflightweight materials, i.e. cast aluminum. By precluding the use oflightweight materials, the weight of heavier prior offset bushingdesigns disadvantageously limit the fuel economy and handling of thevehicle.

In light of the above, a need exists for an offset bushing designincorporated into lightweight suspension components, such as castaluminum suspension components.

SUMMARY OF THE INVENTION

Embodiments of the present invention may overcome the drawbacksassociated with the prior art by providing a lightweight suspensioncomponent having an offset bushing assembly. Systems and methods forproviding a lightweight suspension component having an offset bushingassembly are disclosed herein. According to aspects illustrated herein,there is provided a suspension assembly including a bolt made from abolt material; a suspension component made from a suspension material,the suspension component having a suspension opening therethrough, thesuspension opening having a geometry for insertion of at least a firstportion of the bolt; and a bushing assembly including an elastomericelement and a bushing opening therethrough, the bushing opening having ageometry for insertion of at least a second portion of the bolt; whereinthe suspension material has a yield strength that is substantiallyhigher than a yield strength of the bolt material.

According to aspects illustrated herein, there is provided a suspensionassembly including a suspension component including at least onesubstantially cylindrical cavity positioned at one end of the suspensioncomponent, the cylindrical cavity providing for attachment to a vehicleframe and having a bore at one end of the cylindrical cavity; a studpositioned centrally in the at least one substantially cylindricalcavity, the stud having a head opposed to enlarged bore of thecylindrical cavity of the suspension component and providing the pivotaxis of the suspension component to a vehicle frame; a hardened sleevein a pressed interference-fit engagement to the enlarged bore of thecylindrical cavity; a bushing assembly including an elastomeric elementhaving a core with a centrally positioned hollow, wherein the hollow ofthe core has a geometry for insertion of the stud; and a fastener inengagement to the stud, wherein the core is positioned between thefastener and the hardened sleeve.

According to aspects illustrated herein, there is provided a method ofmanufacturing a suspension assembly including providing a suspensioncomponent including at least one cavity positioned at one end of thesuspension component, the at least one cavity providing for attachmentto a vehicle frame, the at least one cavity having an enlarged bore atone end thereof; positioning a stud in the at least one cavity of thesuspension component, the stud having a head in contact with a portionof the suspension component opposed to the enlarged bore of the at leastone cavity of the suspension component; positioning a sleeve over thestud and adjacent to the enlarged bore of the at least one cavity of thesuspension component; positioning a bushing assembly having anelastomeric element with a core, the core having a first end, a secondend and a hollow, wherein the stud is positioned within the hollow ofthe bushing assembly and the first end of core is adjacent to thesleeve; and engaging a fastener adjacent to the second end of the coreand in threaded connection to the stud, wherein full engagement of thefastener further presses the sleeve into the enlarged bore of the atleast one cavity and clamps the core of the bushing to the sleeve.

Various embodiments provide certain advantages. Not all embodiments ofthe invention share the same advantages and those that do may not sharethem under all circumstances. Further features and advantages of theembodiments, as well as the structure of various embodiments aredescribed in detail below with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The presently disclosed embodiments will be further explained withreference to the attached drawings, wherein like structures are referredto by like numerals throughout the several views. The drawings shown arenot necessarily to scale, with emphasis instead generally being placedupon illustrating the principles of the presently disclosed embodiments.

FIG. 1 is a stress diagram of an illustrative embodiment of a priorsuspension component having a prior offset bushing design;

FIG. 2 is a perspective view of an illustrative embodiment of asuspension component having an offset bushing assembly;

FIG. 3 is a cross-sectional view of an illustrative embodiment takenalong section line 2-2 of the offset bushing depicted in FIG. 2;

FIG. 4 is a stress diagram of an illustrative embodiment of an offsetbushing and suspension component;

FIG. 5 is a stress diagram of all illustrative embodiment of an offsetbushing and suspension component;

FIG. 6 is a stress diagram of an illustrative embodiment of an offsetbushing and suspension component;

FIG. 7 is a stress diagram of an illustrative embodiment of an offsetbushing and suspension component;

FIG. 8 is a cross-sectional view of an illustrative embodiment of anoffset suspension bushing;

FIG. 9 is a stress diagram of the offset suspension bushing of FIG. 8;

FIG. 10 is a cross-sectional view of an illustrative embodiment of anoffset suspension bushing;

FIG. 11 is a stress diagram of the offset suspension bushing of FIG. 10;

FIG. 12 is a cross-sectional view of an illustrative embodiment of anoffset suspension bushing; and,

FIG. 13 is a stress diagram of the offset suspension bushing of FIG. 12.

While the above-identified drawings set forth presently disclosedembodiments, other embodiments are also contemplated, as noted in thediscussion. This disclosure presents illustrative embodiments by way ofrepresentation and not limitation. Numerous other modifications andembodiments can be devised by those skilled in the art which fall withinthe scope and spirit of the principles of the presently disclosedembodiments.

DETAILED DESCRIPTION OF THE DRAWINGS

The inventions are not limited in its application to the details ofconstruction and the arrangement of components set forth in thefollowing description or illustrated in the drawings. The inventions arecapable of being arranged in other embodiments and of being practiced orof being carried out in various ways. Also, the phraseology andterminology used herein is for the purpose of description and should notbe regarded as limiting. The use of “including,” “comprising,” or“having,” “containing,” “involving,” and variations thereof herein, ismeant to encompass the items listed thereafter and equivalents thereofas well as additional items.

Aspects of the inventions are described below with reference toillustrative embodiments. It should be understood that reference tothese illustrative embodiments is not made to limit aspects of theinventions in any way. Instead, illustrative embodiments are used to aidin the description and understanding of various aspects of theinventions. Therefore, the following description is intended to beillustrative, not limiting.

Embodiments of the present invention are directed to a disposableapparatus. As shown in the embodiment of FIG. 2, a suspension component10 may have an offset bushing assembly 15. The suspension component 10may be a triangular A-arm configuration in which one end, forming thevertex 12 of the triangle, may provide for engagement to a ball joint orequivalent structure, and may further include two suspension legs 13 a,13 b extending from the vertex 12 of the suspension component 10 and mayprovide for a pivoting engagement to a vehicle frame (not shown). Thepivoting engagement may be provided by cavities 11, having asubstantially cylindrical configuration, formed through the portion ofthe suspension legs 13 a, 13 b attached to the vehicle frame incombination with bushings connected to the cavities 11, wherein at leastone bushing may be an offset bushing assembly 15. In some embodiments, afirst suspension leg 13 a may be connected to the vehicle frame by anoffset bushing assembly 15, and the second suspension leg 13 b may beconnected to the vehicle frame by a conventional bushing assembly, inwhich the conventional bushing may fit within the cavity 11.

Although the suspension component 10 is depicted as having theconfiguration of a triangular A-arm, the suspension component 10 may beany suspension member that is utilized in automotive applicationsincluding but not limited to: swing arm, control arm, drag link,differential link, camber link, lateral link, trailing arm, strut rod,trailing arm, tie rod, knuckle, wheel carrier, subframe, axle carrier,crossmember, subframe and toe rods. In addition, the suspensioncomponent may be used on any vehicle, including but not limited to anautomobile, truck, semi, bus, van, minivan, sports utility vehicle(SUV), motorcycle, bicycle, scooter, carriage, train, boat, ship,submarine, amphibious vehicle, all-terrain vehicle (ATV), aeroplane,rotorcraft, or any other device or structure for transporting persons orthings. Not all embodiments of the present invention are intended to belimited in these respects.

The suspension component 10 may be composed of a lightweight material.Using a lightweight material may contribute to increasing at least oneof the performance and fuel economy of the vehicle. The suspensioncomponent 10 may be composed of an aluminum alloy, for example, AluminumAssociation A356. In some embodiments, the aluminum alloy may becomposed of from about 6.5 wt. % to about 7.5 wt. % Al, less than 0.20wt. % Fe, less than 0.20 wt. % Cu, less than 0.10 wt. % Mn, from about0.25 wt. % to about 0.45 wt. % Mg, less than 0.10 wt. % Zn, less than0.20 wt. % Ti, and a balance of Al and incidental impurities. Incidentalimpurities may include any contamination of the melt, including leachingof elements from the casting apparatus. Allowable ranges of impuritiesmay be less than 0.05 wt. % for each impurity constituent and 0.15 wt. %for total impurity content. In some embodiments, the casting may be heattreated to a T5 or T6 temper. In some embodiments, the temper may be aT6 temper.

The suspension component may be cast using permanent mold castingtechnology, sand casting technology, or a Vacuum Riserless Casting(VRC)/Pressure Riserless Casting (PRC). The Vacuum Riserless Casting(VRC)/Pressure Riserless Casting (PRC) process may be suitable for massproduction of high integrity aluminum automotive suspension components.VRC/PRC is a low pressure casting process, in which in some embodimentsthe pressure may be on the order of 6.0 Psi. In some embodiments thepressure may be between approximately 3.5 Psi and approximately 8.5 Psi,may be less than 6.0 Psi or may be greater than 6.0 Psi as not allembodiments of the present invention are intended to be limited in thisrespect. In VRC/PRC, a mold may be positioned over a hermetically sealedfurnace and the casting cavity may be connected to the melt by feedtubes. Melt may be drawn into the mold cavity by applying a pressure tothe furnace through the application of an inert gas, such as Argon. Aconstant melt level may be maintained in the·furnace of the VRC/PRCapparatus, which may assist in avoiding back-surges that are sometimesexperienced in a more traditional low-pressure system.

Multiple fill tubes (stalks) may provide for metal distribution in themold cavity. Multiple fill points combined with close coupling betweenthe mold and melt surface may allow for lower metal temperatures, mayminimize hydrogen and oxide contamination and/or may provide maximumfeeding of shrinkage-prone areas in the casting. The multiple fill tubesmay also allow multiple yet independent cavities in a mold. Carefullysequenced thermal controls may quickly solidify castings from extremeback to fill tubes, which may then function as feed risers.

The suspension component may be a hollow casting. Although, in someembodiments, the suspension component 10 may be cast, the suspensioncomponent may be formed or forged.

The embodiment depicted in FIG. 3 shows a cross sectional view of alongsection line 2-2 of the offset bushing assembly 15 connected to thefirst suspension leg 13 a, as depicted in the embodiment shown in FIG.2. The cavity in the first suspension leg 13 a may further include anenlarged bore 16. The enlarged bore 16 may have a width W1 and length L1dimension which may provide for a frictional and/or Interference-fitengagement to the hardened sleeve 25 of the offset bushing assembly 15.In some embodiments, a hardened sleeve may have a strength which isgreater than a normal material by subsequent processing in an attempt toincrease wear and resist higher stresses without failure.

In some embodiments, the enlarged bore 16 may be machined into thecavity 16 of the first suspension leg 13 a. The portion of thesuspension component 10 corresponding to the cavity 11 may have a firstflange 14 a corresponding to a first opening 17 a of the cavity 11having the enlarged bore 16, and a second flange 14 b corresponding to asecond opening 17 b of the cylindrical cavity 11 that is opposed to theenlarged bore 16. The first and second flanges 14 a, 14 b may strengthenthe portion of the suspension component 10 corresponding to the cavity11 and may provide sufficient area to react to loads of head portion 21of the stud 20 and lateral rim portion of the hardened steel sleeve 25and in some embodiments, react without deformation.

Referring to FIG. 2 and FIG. 3, in one embodiment, the offset bearingassembly 15 includes a stud 20, a sleeve 25, a fastener 30, and abushing assembly including an elastomeric element 40. Referring to FIG.3, the stud 20 may be formed from hardened steel and may include a headportion 21 and a threaded portion 22. The head portion 21 has a width W3greater than the width W4 of the first opening 17 a, wherein the widthof the first opening 17 a is substantially equal to provide aninterference fit to the width of the cylindrical cavity 11 prior to theenlarged bore 16. The threaded portion 22 may extend a portion of thelongitudinal length L2 of the stud 20 or may be positioned only tocorrespond with the threaded fastener 30.

The sleeve 25 may be composed, such as by forming or casting, of amaterial having a higher hardness than the suspension component 10. Insome embodiments, this material may be hardened steel. The sleeve 25 mayhave a width for frictional engagement of the exterior surface of thelongitudinal body portion 18 of the hardened sleeve 25 to the interiorsurface of the enlarged bore 16 in a pressed interference-fitengagement. Specifically, the properties of the pressed engagement maybe enhanced by selecting the width of W₁ of the enlarged portion 16 ofthe cavity, the width W₂ of the hardened sleeve 25, the wall thicknessT1 of the hardened sleeve 25, and the thickness of W5 of the suspensionleg 13 to provide a compressive force induced by the interior surface ofthe enlarged portion 16 of the cavity 11. This compressive force is themechanism that provides the sufficient normal force to frictionallyengage hardened sleeve 25 and enlarged portion 16 of cavity 11.

In some embodiments, choosing a material which is harder or has a higheryield strength for a first part, such as the stud and/or bolt, mayenable a lower strength and/or lighter weight material to be used foranother part, such as the boss or suspension component. The yieldstrength or yield point of a material is the stress at which thematerial begins to deform plastically. Prior to the yield point, amaterial may deform elastically and will return to its original shapewhen an applied stress is removed. Once the yield point of a material ispassed, some fraction of deformation will be permanent andnon-reversible. A material's yield point may be defined as thematerial's true elastic limit, e.g., the lowest stress at whichdislocations move, as the material's proportionally limit, e.g., thepoint at which the stress-strain cure deviates from Hooke's law (i.e.,becomes non-linear), as the material's elastic limit, e.g., the loweststress at which permanent deformation may be measured, as the material'soffset yield point (yield strength or proof stress), e.g., the point onthe stress strain curve, typically defined by a plastic strain of 0.2%,and/or as the material's upper and/or lower yield points, e.g., thepoint at which the material reaches an upper yield point before droppingrapidly to a lower yield point, wherein the material response may belinear up until the upper yield point, but the lower yield point may beused in structural engineering as a conservative value.

In some embodiments, the boss or suspension component may be made from afirst material and the stud or bolt may be made from a second material.The second material may have a yield strength that is substantiallyhigher than the yield strength of the first material. In someembodiments, the second material may have a yield strength that is twoor three times higher than the yield strength of the first material. Insome embodiments, the second material may have a yield strength that ismore than three times higher than the yield strength of the firstmaterial. In some embodiments, the first material may have a yieldstrength of approximately 200 MPa. In some embodiments, the yieldstrength of the first material may range from approximately 100 MPa toapproximately 300 MPa. The yield strength of the first material may beless than 100 MPa or may be greater than 300 MPa, as not all embodimentsof the present invention are intended to be limited in this respect. Insome embodiments, the second material may have a yield strength ofapproximately 800 MPa. In some embodiments, the yield strength of thesecond material may range from approximately 600 MPa to approximately800 MPa and/or from approximately 800 MPa to approximately 1000 MPa. Theyield strength of the second material may be less than 600 MPa or may begreater than 1000 MPa, as not all embodiments of the present inventionare intended to be limited in this respect. In some embodiments, thesecond material may include steel or titanium or any other materialhaving a higher yield strength than the first material, which mayinclude, but is not limited to, aluminum or magnesium alloys, or a lowerstrength steel or iron.

It should be appreciated that in some embodiments, some of thecomponents or parts of the bushing suspension may be made from a higheror lower yield strength materials, as not all embodiments of the presentinvention are intended to be limited in this respect.

The longitudinal body 18 portion may have dimensions for insertion ofthe hardened sleeve 25 within the enlarged bore 16 of the cavity 11. Thehardened sleeve 25 may further include a lateral rim portion 17extending along an exterior surface of the first flange 14 a of thesuspension component 10. The lateral rim 17 may facilitate distributionof the load stresses induced in the bushing assembly during service tothe suspension component 10 in a uniform manner.

In one embodiment, the bushing assembly may include an elastomericelement 40 having a rigid core 35 with a centrally positioned hollow.The elastomeric element may be provided by a polyurethane or rubberbushing. In some embodiments, the elastomeric element may be provided bya hydraulic bushing. The hydraulic bushing may include a polyurethane orrubber skin encasing hydraulic oil. Hydraulic bushings may be tuned fora specific frequency and provide increased damping at the tunedfrequency. Compared to a much stiffer conventional bushing, a hydraulicbushing may provide a lower spring rate for improved isolation but muchhigher damping for adequate control. A hydraulic bushing may producehigh damping as a result of the transfer of fluid from one chamber toanother. The fluid may pass through a channel called the inertia track.The inertia track can be ‘tuned’ to provide damping at a specificfrequency. It should be appreciated that any bushing, such as solidbushings, may be utilized.

The rigid core 35 may be provided by a lightweight material, such asaluminum, having sufficient wall thickness to provide structuralrigidity. The hollow that is centrally positioned has a width sufficientfor insertion of the stud 20. In some embodiments, a core flange 36 maybe provided at the end of the rigid core 35 that is opposite thehardened sleeve 25 and engaged by the fastener 30. The core flange 36may reinforce the site at which the fastener 30 engages the rigid core35 in order to clamp it against the hardened sleeve 25 in frictional andinterference-fit engagement to the enlarged bore 16 of the cavity 11.

The fastener 30 positioned at the end of the rigid core 35 opposite thehardened sleeve 25 may be engaged to the stud 20 in communicatingthreaded engagement. The fastener 30 may have a width W₆ that issufficiently greater than the width of the hollow centrally positionedin the rigid core 35. Torquing the fastener 30 into contact with thecore flange 36 may induce a force on the sleeve 25 through the contactof the rigid core 35 to the lateral rim portion 17 of the sleeve 25,wherein continued torquing of the fastener 30 towards the cavity 11 ofsuspension component 10 may further press the hardened sleeve 25 intofrictional engagement with the enlarged bore. In some embodiments, thefastener 30 may be composed of a hardened steel or another high yieldstrength material.

In another aspect of the present invention, a method of forming asuspension component assembly having an offset bushing is provided. Themethod may include the steps of providing a suspension component 10including at least one substantially cylindrical cavity 11 positioned atone end of the suspension component 10, the cylindrical cavity 11providing for attachment to a vehicle frame and having an enlarged bore16 at one end of the cylindrical cavity 11; positioning a stud 20centrally in the at least one substantially cylindrical cavity 11 of thesuspension component 10, the stud 20 having a head 21 in contact with aportion of the suspension component 10 opposed to enlarged bore of thecylindrical cavity 11 of the suspension component; positioning ahardened sleeve 25 over the stud 20 and adjacent to the enlarged bore 16of the cylindrical cavity of the suspension component 10; positioning abushing assembly having an elastomeric element 15 with a rigid core, therigid core 35 having a first end, a second end and a centrallypositioned hollow, wherein the stud 20 is positioned within thecentrally positioned hollow of the bushing assembly 15 and the first endof rigid core 35 is adjacent to the hardened sleeve 25; and engaging afastener 30 adjacent to the second end of the rigid core 35 and inthreaded connection to the stud, wherein full engagement of the fastener30, clamps the rigid core 35 of the elastomeric element 15 to thehardened sleeve 25, further pressing the hardened sleeve 25 into theenlarged bore 16 of the cylindrical cavity 11.

In one embodiment, a suspension assembly includes a suspension componentincluding at least one substantially cylindrical cavity positioned atone end of the suspension component, the cylindrical cavity providingfor attachment to a vehicle frame and having an enlarged bore at one endof the cylindrical cavity; a stud positioned centrally in the at leastone substantially cylindrical cavity, the stud having a head opposed toenlarged bore of the cylindrical cavity of the suspension component andproviding the pivot axis of the suspension component to a vehicle frame;a hardened sleeve in a pressed engagement to the enlarged bore of thecylindrical cavity; a bushing assembly including an elastomeric elementhaving a rigid core with a centrally positioned hollow, wherein thehollow of the rigid core has a geometry for insertion of the stud; and afastener in engagement to the stud, wherein the rigid core is positionedbetween the fastener and the hardened sleeve.

In some embodiments, the suspension component may be cast from alightweight and/or lower yield strength material, such as an aluminumalloy, and at least one of the stud and the hardened sleeve may beformed of steel or a higher yield strength material. The hardened sleevemay provide a relatively high strength material that uniformlydistributes the service loads induced to the offset bushing to thelightweight cast suspension component.

In some embodiments, the suspension component may include an aluminumalloy. In some embodiments, the suspension component may include atleast one of a swing arm, a control arm, a drag link, a differentiallink, a camber link, a lateral link, a trailing arm, a strut rod, atrailing arm, a tie rod, a knuckle, a wheel carrier, a subframe, an axlecarrier, a crossmember, a subframe and a toe rod. In some embodiments,the suspension component may have an A-arm configuration, having atleast two cylindrical cavities providing for attachment to a vehicleframe. In some embodiments, the hardened sleeve may include steel. Insome embodiments, the core of the bushing assembly may be a rigid coreand may include steel. In some embodiments, the rigid core may includean enlarged flange positioned adjacent to the fastener.

In some embodiments, the end of the suspension component having thesubstantially cylindrical cavity may have a first flange correspondingto a first opening of the cylindrical cavity having the enlarged boreand a second flange to a second opening of the cylindrical cavityopposed to the enlarged bore. In some embodiments, the hardened sleevemay include a longitudinal body portion and a lateral rim portion; thelongitudinal portion may have dimensions for insertion to the enlargedbore of the cylindrical cavity and the lateral rim portion may extendalong an exterior surface of the first flange of the suspensioncomponent. In some embodiments, the hardened sleeve may uniformlydistribute service loads induced to the bushing assembly to thesuspension component. In some embodiments, the elastomeric element maybe a hydraulic bushing. In some embodiments, the elastomeric element mayinclude polyurethane, rubber or a combination thereof. In someembodiments, the stud may include steel.

Some embodiments of the suspension assembly of the present invention mayprovide for a more uniform distribution of the bending stresses in themain body of the suspension component 10 generated by an offset bushingconfiguration than were previously possible in prior offset bushingconfigurations. In some embodiments, the hardened sleeve 25 may moreuniformly distribute highly concentrated stresses at the pivot axis ofthe bushing assembly to the lower-strength material of the suspensioncomponent.

The embodiments depicted in FIGS. 4-7 show stress distributions measuredin one embodiment of the offset bushing and suspension componentassembly, wherein a force F of 33.2 kN is being subjected to thebushing, as typically experienced in automotive or light truckapplications. FIG. 4 depicts the stress distribution throughout theentire structure. FIG. 5 depicts the stress distribution to thestructure without showing the rigid collar 35. FIG. 6 depicts the stressdistribution to the structure without showing the rigid collar 35 andstud 20. FIG. 7 depicts stress distribution in the suspension component10 without showing the rigid collar 35, the stud 20, and the hardenedsleeve 17. As depicted in FIG. 7, a measurable reduction in the stressinduced to the suspension component 10 may be provided by the hardenedsleeve 17 and offset bushing assembly, wherein a reduction in stress toless than 300 MPa at the connection 100 of the bushing 15 to thesuspension component 10 allows for the use of lightweight aluminum alloysuspension components in an advantageous manner, such as an economicalmanner.

As shown in the embodiments depicted in FIG. 8, a sleeve 202 may be usedto transmit a load from a bushing (not shown) to a suspension component,which may contain or may be rigidly affixed to a boss 204. The sleeve202 may be a stepped, hardened steel sleeve and may be designed towithstand high stresses without permanent deformation or fracture. Thesleeve 202 may be designed to spread out the load from the bushing to alarge contact area of the suspension component or boss 204. The boss 204may be formed separately from or integrally with the sleeve 202. In someembodiments, the boss 204 is made from cast aluminum. The boss 204 maybe aligned with the sleeve 202 to enable a bolt 210 to be insertedthrough bores 206, 208 of the sleeve 202 and boss 204, respectively. Thebolt 210 may be threaded into a fastener, such as a nut (not shown), onthe outside of the bushing inner sleeve to hold the bolt 210 in place.This configuration may clamp the bushing inner metal and sleeve 202 tothe boss 204, thereby contributing to proper load transfer throughfrictional forces. Stresses acting on the boss 204, for example stressesdue to service loading, may be effectively reduced such that alower-strength material can now be utilized and may withstand repeatedapplication of the service load. An exemplary stress distribution isrepresented in the embodiment shown in FIG. 9.

In some embodiments, an adaptor or connector may be utilized to transmita load from a bushing to a suspension component, similar to the sleeve202 of the previous embodiment. As shown in the embodiment depicted inFIG. 9, a cantilever bushing joint 220 may include a boss 222 and abushing 224 connected to the boss via an adaptor 226. The bushing 224may be press fit or interference fit onto the adaptor 226. The adaptor226 may connect with the boss 222 via a contact surface 228.

The contact surface 228 may be formed in mushroom or convex shape, whichmay improve stress distribution for the contact surface 228 between theadaptor 226 and the suspension component or the boss 222. A contactsurface with a mushroom shape may also limit and resist slippage betweenthe adaptor and the suspension component. In some embodiments, theadaptor 226 is made of a material which can withstand high stresseswithout significant or any deformation, similar to a steel sleeve 202 asdescribed above.

A bolt 230 may be inserted through bores of the boss 222, adaptor 226and bushing 224. The bolt 230 may be secured in place using any means,such as a nut 232 or other fastener positioned a distal end 234 of thebushing 224. In some embodiments, the nut 232 may be threaded onto thesteel bolt 230 outside of the bushing inner sleeve, which may clamp thebushing inner metal and adaptor to the suspension component, assistingin attaining proper load transfer through frictional forces. Thestresses acting on the suspension component due to the service loadingmay be effectively reduced such that a lower-strength material can nowbe utilized, and may withstand repeated application of the service load.An exemplary stress distribution is represented in the embodiment shownin FIG. 11.

In some embodiments, the adaptor portion may be combined with thebushing inner sleeve, as shown in the embodiment depicted in FIG. 12.The cantilever bushing joint 240 may include a boss 242 and anintegrated bushing sleeve 244. The integrated bushing sleeve 244 may bedesigned to transmit a load from the bushing to the suspension componentor the boss 242, similar to the steel sleeve 202 of FIG. 8. The contactsurface 246 may be formed in a mushroom shape, which may betterdistribute stress between the bushing and the suspension component. Asdescribed above, the bushing sleeve may be made of a material which canwithstand high stresses without significant or any deformation. In someembodiments, a steel bolt 248 may be secured by a nut 250 threaded ontoa distal end 252 of the steel bolt 148. An exemplary stress distributionis represented in the embodiment shown in FIG. 13. In some embodimentshaving an integrated bushing sleeve, the bushing inner metal may be madeof a similar or the same high yield strength material as the adaptor 226of the embodiment depicted in FIG. 10; this material may be needed towithstand service-induced stresses.

It should be appreciated that interference fit or press fit may implythat one part is pressed into another part to hold the first part inplace. In some embodiments, the first part may have a bigger diameterthan an opening in the second part into which the first part isinserted. When the first part is inserted or forced into the opening inthe second part, the second part may deform to accommodate the firstpart. This deformation may be microscopic or visible with the naked eye.The first part may then be held by frictional forces caused by thenormal forces of the second part trying to return to its original shape.In other words, the elastic deformation of the second part may hold thefirst part in place by substantial frictional force between the parts.

It will be appreciated that several of the above-disclosed and otherfeatures and functions, or alternatives thereof, may be desirablycombined into many other different systems or applications. Variouspresently unforeseen or unanticipated alternatives, modifications,variations, or improvements therein may be subsequently made by thoseskilled in the art which are also intended to be encompassed by thefollowing claims.

1. A service load bearing assembly, comprising: a load distributionassembly comprising an offset bushing having a bushing contact area that(i) serves as a bushing for a service load between a pivot axiscomponent and a suspension component, (ii) mates with a suspensioncomponent contact area, and (iii) functions to spread-out the serviceload from the bushing, through the bushing contact area, and onto thesuspension component contact area; wherein, the pivot axis component hasa yield strength that is at least 2 times higher than a yield strengthof the suspension material; the suspension component comprises asuspension material, the suspension component having a geometry forinsertion of at least a first portion of the pivot axis component; andthe bushing is offset from the suspension component contact area throughthe load distribution assembly such that a stress induced by the serviceload is spread out to an amount that is at or below the yield strengthof the suspension component.
 2. The assembly of claim 1, wherein thesuspension material has a component selected from the group consistingof aluminum, aluminum alloys, magnesium, magnesium alloys, low yieldstrength steel, iron, and low yield strength materials having a yieldstrength of at least about 100 MPa and about 300 MPa.
 3. The assembly ofclaim 1, wherein the yield strength of the pivot axis component is atleast three times higher than the yield strength of the suspensioncomponent.
 4. The assembly of claim 1, wherein the yield strength of thepivot axis component is between about 600 MPa and about 1000 MPa and theyield strength of the suspension component is between about 100 MPa andabout 300 MPa.
 5. The assembly of claim 1, wherein the pivot axiscomponent comprises a high strength steel or titanium and the suspensioncomponent comprises aluminum, aluminum alloy, magnesium, magnesiumalloy, a low strength steel or iron.
 6. The assembly of claim 1, whereinthe pivot axis component material is a high strength steel and thesuspension component material is an aluminum alloy.
 7. The assembly ofclaim 1, wherein the load distribution assembly has a bushing assemblythat includes an adaptor and a bushing sleeve, the adaptor beingarranged to contact the suspension component.
 8. The assembly of claim7, wherein the bushing sleeve comprises an elastomeric material.
 9. Theassembly of claim 1, wherein the bushing contact area has a mushroom orconvex shape.
 10. The assembly of claim 1, wherein the load distributionassembly comprises a hydraulic bushing.
 11. A suspension assembly,comprising: a pivot axis component comprising a material having acomponent selected from the group consisting of a high yield strengthsteel, titanium, and a high yield strength material having a yieldstrength greater than about 600 MPa; a suspension component comprising asuspension material, the suspension component having a suspensionopening therethrough, and the suspension opening having a geometry forinsertion of at least a first portion of the pivot axis component, thesuspension material having a component selected from the groupconsisting of aluminum, aluminum alloys, magnesium, magnesium alloys,low yield strength steel, iron, and low yield strength materials havinga yield strength between about 100 MPa and about 300 MPa; and, a loaddistribution assembly comprising an offset suspension bushing having abushing contact area that (i) serves as a bushing for a service loadbetween the pivot axis component and the suspension component, (ii)mates with a suspension component contact area, and (iii) functions tospread-out the service load from the bushing, through the bushingcontact area, and onto the suspension component contact area; wherein,the pivot axis component has a yield strength that is at least 2 timeshigher than a yield strength of the suspension material; and the bushingis offset from the suspension component contact area through the loaddistribution assembly such that a stress induced by the service load isspread out to an amount that is at or below the yield strength of thesuspension component.
 12. The suspension assembly of claim 11, whereinthe yield strength of the pivot axis component is at least three timeshigher than the yield strength of the suspension component.
 13. Thesuspension assembly of claim 11, wherein the yield strength of the pivotaxis component is between about 600 MPa and about 1000 MPa and the yieldstrength of the suspension component is between about 100 MPa and about300 MPa.
 14. The suspension assembly of claim 11, wherein the pivot axiscomponent material is a high strength steel and the suspension componentmaterial is an aluminum alloy.
 15. The suspension assembly of claim 11,wherein the load distribution assembly has a bushing assembly thatincludes an adaptor and a bushing sleeve, the adaptor being arranged tocontact the suspension component.
 16. The suspension assembly of claim15, wherein the bushing sleeve comprises an elastomeric material. 17.The suspension assembly of claim 11, wherein the bushing contact areahas a mushroom or convex shape.
 18. The suspension assembly of claim 11,wherein the load distribution assembly comprises a hydraulic bushing.19. A suspension assembly comprising: a suspension component includingat least one cylindrical or substantially cylindrical cavity positionedat one end of the suspension component, the cylindrical cavity providingfor attachment to a vehicle frame and having a bore surface at one endof the cylindrical cavity; a pivot axis component positioned centrallyin the at least one cylindrical or substantially cylindrical cavity, thepivot axis component (i) having a head surface that is opposed to thebore surface of the cylindrical cavity of the suspension component and(ii) providing a pivot axis for the suspension component when attachedto the vehicle frame through a bushing comprising an elastomeric elementand a rigid core with a centrally positioned hollow; and, a hardenedsleeve in a pressed interference-fit engagement with the bore of thecylindrical cavity and having a first contact area for applying a loadon the suspension component from the bushing, such that a stress inducedby the service load is spread out to an amount that is at or below theyield strength of the suspension component; wherein, the elastomericelement having the rigid core with the centrally positioned hollow and asecond contact area for applying the load to the hardened sleeve,wherein the hollow of the rigid core has a geometry for insertion of thepivot axis component; wherein, the first contact area is larger than thesecond contact area; and, the concentrated stress is reduced to anamount that is at or below the yield strength of the suspensioncomponent.
 20. The suspension assembly of claim 19, wherein the yieldstrength of the pivot axis component is at least three times higher thanthe yield strength of the suspension component.
 21. The suspensionassembly of claim 19, wherein the yield strength of the pivot axiscomponent is between about 600 MPa and about 1000 MPa and the yieldstrength of the suspension component is between about 100 MPa and about300 MPa.
 22. The suspension assembly of claim 19, wherein the pivot axiscomponent is a high strength steel and the suspension component is analuminum alloy.
 23. The suspension assembly of claim 19, wherein theload distribution assembly has a bushing assembly that includes anadaptor and a bushing sleeve, the adaptor being arranged to contact thesuspension component.
 24. The suspension assembly of claim 19, whereinthe first contact area has a mushroom or convex shape.